Santa Luz is the community that you see to either side of Camino del Sur as you head north of Hwy 56. Technically, I guess it begins as you pass Carmel Mountain Road heading North, and it ends when Camino del Sur ends a couple miles beyond that intersection. Keep heading North and you’ll get to the new community of Del Sur.
The part that is East of Camino del Sur is generally low density (near the golf course), while the part West of Camino del Sur features homes in the 3000-4000 sq ft range on fairly small lots, similar to Carmel Valley.
Lastly, you CAN get to Escondido / Poway from RSF if you just take county road S-7 (?) that heads due east from the village of RSF. It’s mainly a 2-lane road that goes past the new Crosby / Links / El Cielo subdivisions and then along the Western part of Lake Hodges. It’s hardly an interstate, but probably a bit quicker than heading down to 56 and then over to I-15.